Ok so you are happy with this?

    Model
        .where(...)
        .foo { ... }
        .flatten
        .bar { ... }
        .join(...)

In Visual studio it doesn't really make a difference from a debugging perspective. However in other debugging tools perhaps it does, and in that case I would tend to agree. But then this is a minor point, something that can be covered with a coding standard and linting the source.

Actually, yes. That's exactly what I'm advocating. Whether they are separate assignments or just chains broken up into multiple lines, the end is the same as far as what I'm talking about.

> It isn't, though. My point is that sticking chains on one line makes it difficult to read as well as debug the various bits and pieces that all rest on a single line.

The thing is, if you want to split the line into multiple lines you have to introduce local variables all over. I actually find this harder and more cumbersome to read because if you are reading the rest of the function, you want to know if these are used anywhere (assuming imperative language). If you have everything on a single line, then you know that the intermediate values are not used anywhere else.

I agree that the line number thing is helpful though. However, if you realize you have a bug you'll likely have to reproduce it anyway, and at that time you can introduce local variables just to see where you went wrong.

Perhaps in the end this is just subjective? This style is very common in functional programming (which I prefer) so maybe that's why I like it and hate having more local variables to keep track of.

Whether you need to introduce variables is dependent on the language. Some allow for chains to continue onto a newline, while others won't.

At this point this is boiling down a subjective argument on readability and tradeoffs in tooling, so no point in continuing. Have a great day!